As portable devices become more compact, and the amount of information to be processed and stored increases, it has become a significant challenge to design a user interface that allows users to easily interact with the device. This is unfortunate since the user interface is the gateway through which users receive not only content but also responses to user actions or behaviors, including user attempts to access a device's features or tools. Some portable communication devices (e.g., mobile phones) have resorted to adding more pushbuttons, increasing the density of push buttons, overloading the functions of pushbuttons, or using complex menu systems to allow a user to access, store and manipulate data. These conventional user interfaces often result in complicated key sequences and menu hierarchies that must be memorized by the user. In addition, as the number of pushbuttons has increased, the proximity of neighboring buttons often makes it difficult for users to activate a desired pushbutton.
Many conventional user interfaces, such as those that include physical pushbuttons, are also inflexible. This is unfortunate because it may prevent a user interface from being configured and/or adapted by either an application running on the portable device or by users. When coupled with the time consuming requirement to memorize multiple key sequences and menu hierarchies, and the difficulty in activating a desired pushbutton, such inflexibility is frustrating to most users.
The interfaces for call waiting and conference calling that are currently available suffer the same shortcomings. Users are often at a loss as to the sequence of buttons to push in order to switch between calls or to make a conference call. Furthermore, the interface often does not convey intuitively the parties involved in the calls.
Accordingly, there is a need for more efficient interfaces for call waiting and conference calling.